1. Field of the Invention
The present invention concerns a linear stalk separator with alternating oscillating movements.
More precisely, it concerns a stalk separator for the de-stalking of small fruit harvested in bunches, in particular, for the de-stalking of grapes.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
In most applications of wine-making or vinification, grapes are first de-stalked before the crop is mashed. The aim of this operation is to detach the berries from the bunches of grapes, thereby, to separate berries from the stalks to which they are attached. In this way, the presence of bitterness and of herbaceous and plant material taste in the wine is avoided.
Various types of apparatus are known which allow de-stalking of small fruit presenting themselves in the form of bunches, likes grapes in particular.
French Patent Document FR-2 669 193, for instance, describes a grape stalk separator-sorter which includes a rotating cylindrical drum with a horizontal or slightly inclined axis. This rotating drum is provided with perforations so as to form a sieve capable of letting the berries pass which have been stripped off the stalks by the action of a rotating scraper roll mounted in said drum and consisting of a shaft on which are fastened radial pegs that are helicoidally implanted along said shaft.
The drum and the spiked roll rotate in the same direction at different speeds or in opposite directions. This rotation allows separating the grapes from the stalks. The grapes are fed into one of the ends of the drum. The berries and the juice pass through the perforations of the drum and are ejected at the other end of the drum.
European Patent Document EP-1 002 467 describes a machine that is specifically made for de-stalking grapes and consists of a linear or plane de-stalker, consisting on the one hand of an endless open conveyor belt on which the fruit to be de-stalked is transported and, on the other hand, a succession of spiked rolls (generally three or four in the machines produced according to this document) that are positioned transversally above said conveyor belt. These spiked rolls turn at a speed proportional to the forward travel speed of the open conveyor belt. The effect of these two movements is to separate the berries from the stalks. The berries and the juice pass through the screen formed by the open conveyor belt, whereas the grape stalks are ejected at the end of said conveyor belt.
The devices described in the two aforementioned documents present several major drawbacks, such as:                excessive crushing of the berries which produced juice;        a fairly large space requirement;        constructive complexity;        high cost; and        limited reliability.        
Also known (see French patent documents FR-2.511.849 and 2.516.755) is a grape de-stalking machine operating through the agitation of the grapes on an oscillating grid, by means of agitator fingers located along the travel of the grapes moving back and forth in the cross direction.
The drawback of such a machine, aside from its low output, is to turn the grapes into pulp which hinders the separation and elimination of various debris contained in it (fragments of leaves, small pieces of wood, leaf stalks, small insects, etc. because of the sticky consistency of the pulped grapes.